CN203035421U - Conical spray injector nozzle matching parts - Google Patents

Abstract

The utility model discloses an umbrella jet fuel injection nozzle coupling, which is a precision coupling composed of a needle valve and a needle valve body. A tapered sealing section is arranged between the needle valve and the needle valve body. There is a through hole in the lower part of the sealing section of the body, and the head of the needle valve has an umbrella-shaped protrusion, and the protruding head can pass through the through hole in the head of the needle valve body. It is characterized in that: the umbrella-shaped The neck of the protrusion of the structure adopts a rounded straight-line tangential transition and a smooth connection. The tapered surface of the outlet of the needle valve body is provided with a round transition. The edge of the outlet of the needle valve body is provided with rounded corners or chamfered corners. The utility model reduces the stress concentration through the smooth transition neck design, enhances the strength of the head, and reduces the risk of fracture. Rounded corners and chamfered corners are added to the outlet of the needle valve body to improve the flow consistency of the nozzle coupler under high pressure.

Description

An umbrella jet fuel injector assembly

technical field

The utility model relates to the field of diesel injection systems, in particular to an umbrella injection fuel injection nozzle assembly.

Background technique

Dalian University of Technology put forward the theory of umbrella injection in the 1980s and applied for a patent. Later, some improvements were made to the umbrella injector and the second and third generation umbrella injectors were launched. Umbrella jet fuel injector has certain advantages in premixed combustion with early injection due to its large outlet cross section, small spray droplet size, and short penetration distance. However, the umbrella nozzle is improved on the basis of the original needle nozzle. The diameter of the head of the needle nozzle is relatively large, and the diameter of the sealing ring and the lift of the needle valve are relatively large. In addition, the reason why umbrella injectors have not been widely used is that the multi-valve technology of diesel engines is relatively backward and the consistency of multi-cylinder umbrella injectors is poor. The oil beam of the umbrella injector sprays out along the guide surface of the pintle head, and is evenly distributed in the circumferential direction. However, in the past, diesel engines used two-valve technology, and the fuel injectors were all inclined. Therefore, the spray of the umbrella injection nozzle was evenly distributed in the circumferential direction but not along the circumferential direction of the combustion chamber in the cylinder, which was not good for combustion and emissions. .

With the passage of time, the four-valve technology of diesel engines has matured and has been applied to many products. However, the compactness of the diesel engine requires the injector to be smaller, and the more demanding emission regulations make the injection pressure of the diesel engine higher, the fuel injection strategy more flexible and need to switch work in more modes. Therefore, pump nozzles with high fuel injection pressure and high-pressure common rail system are commonly used fuel injection systems at present. Combustion chamber and other advantages, is currently commonly used fuel injector assembly.

According to the low-temperature combustion theory of diesel engines, the mixing process of air and fuel directly affects the combustion and emission processes of diesel engines. The fuel injector is the key interface between the fuel system and the combustion chamber, and is responsible for injecting fuel into the combustion chamber and mixing with air. Its characteristics, such as the spatial distribution of fuel, droplet size, penetration distance and spray cone angle, seriously affect the combustion and emission. At present, direct-injection diesel engines use long nozzle nozzles. Even if a common rail system with small aperture and high injection pressure is used, there are still problems such as long penetration distance, small spray cone angle, and oil jet droplet size. Due to the spray characteristics such as large diameter, the fuel hits the wall, which makes the unburned HC increase and the emission rises. The effective cross-section of the umbrella injector is relatively large, and the high-pressure flow rate is relatively high, but there is a problem that the high-pressure flow difference between the injector and the injector is large, and the poor consistency of the umbrella injector seriously affects the performance of the umbrella injector on the multi-cylinder machine. Applications. Umbrella injectors are designed on the basis of pintle injectors, which cannot meet the compact structure requirements of P series injectors for diesel engines. Therefore, combining the characteristics of the four-valve compact arrangement of the existing diesel engine and the characteristics of high-pressure injection with the advantages of the umbrella injector to improve the design of a new type of umbrella injector will improve the formation of the mixture and reduce emissions.

In addition, in the prior art, the umbrella-shaped structure of the needle valve head of the umbrella injector and the neck connected to the needle valve are straight, and the curvature of the joint of the neck is relatively large, and there is a large stress concentration. During the working process of spraying, the head is easy to break.

Contents of the invention

The purpose of the utility model is to provide an umbrella jet fuel injection nozzle assembly whose head is not easy to break and turn around, and the flow consistency of the nozzle assembly under high pressure is good.

For realizing the above object, the utility model adopts the following technical solutions:

An umbrella injection fuel injector coupler, which is a pair of precision couplers composed of a needle valve and a needle valve body, with a tapered sealing section between the needle valve and the needle valve body, and a There is a through hole, and the head of the needle valve has an umbrella-shaped protrusion, and the protruding head can pass through the through hole of the needle valve body head. It is characterized in that: the umbrella-shaped protrusion The neck adopts a rounded straight line tangential transition, smooth connection.

It is further characterized in that: the lift of the parachute injection nozzle coupler is 0.02mm-1mm.

Further: the tapered surface of the outlet of the needle valve body is provided with a round transition.

The edge of the outlet of the needle valve body is provided with rounded corners or chamfered corners.

The utility model reduces the stress concentration of the neck through the smooth transition neck design, enhances the strength of the head, and reduces the risk of fracture. Rounded corners and chamfered corners are added to the outlet of the needle valve body to improve the flow consistency of the nozzle coupler under high pressure.

Description of drawings

Fig. 1 is the assembly diagram of the couple parts of the utility model patent.

Figure 2 and Figure 3 are enlarged views of the head of the needle valve fully closed and fully opened after the needle valve and the needle valve body are matched.

Detailed ways

The specific structure proposed by the utility model and its usage will be described in detail below in conjunction with the accompanying drawings.

As shown in Figure 1-3, an umbrella injection nozzle coupler is a pair of precision couplers composed of a needle valve 2 and a needle valve body 1. The sealing section has a through hole in the lower part of the sealing section of the needle valve body 1, and the head of the needle valve has an umbrella-shaped protrusion, and the protruding head can pass through the through hole of the needle valve body head. The neck of the protrusion of the umbrella-shaped structure adopts rounded corners and straight-line tangential transitions, and is smoothly connected. The rounded and smooth design minimizes stress concentration, enhances the strength of the needle valve head, and reduces the risk of fracture.

The lift of the parachute injection nozzle coupler is 0.02mm-1mm.

The tapered surface of the outlet of the needle valve body is provided with a round transition. The edge of the outlet of the needle valve body is provided with rounded corners or chamfered corners. Through the adjustment of rounded corners or chamfered corners, the spread of nozzles of the same batch can be controlled within a relatively reasonable range.

Install the fuel injector assembly on the fuel injector, and the fuel injector assembly is in the closed state without spraying, as shown in Figure 2. When the pressure formed by the effective area of the hydraulic system acting on the needle valve exceeds the opening pressure of the spring, the needle valve 2 moves upward, and the needle valve body 1 and the needle valve 2 form a small gap at the sealing line 3, and the fuel passes through the oil tank. Throttle. As the lift of the needle valve increases, the small gap formed between the needle valve 2 and the needle valve body 1 increases, and the throttling point moves downward to the gap formed by the needle valve body outlet fillet 8 and the needle valve sealing line lower cone 4. position, and with the increase of the lift of the needle valve 2, the throttling of the fuel is transferred to the annular gap formed by the guide cone surface 6 and the outlet fillet 8 of the needle valve body. Since the effective flow section of the umbrella fuel injector is relatively large, the rounded corner 8 at the outlet of the needle valve body designed here can increase the effective flow section under most of the lift. After the needle valve 2 is opened, the high-pressure fuel will act on the guide cone 6 protruding from the head. The cone angle α of the guide cone 6 is between 40°-160°, and the pressure formed will be concentrated on the neck 5. , the diameter d of the neck 5 is 0.4mm-1.5mm, and the needle valve neck 5 designed for this is an arc, which is tangent to the tapered surface 4 under the sealing line and the tapered surface 6 extending from the head. After the fuel acts on the guide cone surface 6, the fuel is sprayed out along the cone surface through the throttling ring gap formed by the guide cone surface 6 and the edge fillet 7 of the needle valve outlet, and mixed with air to form a mixture. See Figure 3 when the needle valve is fully open. The closing process is similar, the needle valve 2 moves down, and the throttling position moves from the throttling ring gap formed between the needle valve guide cone surface 6 and the needle valve body to the needle valve body outlet fillet 8 and continues to move to the sealing line 3 and completely off.

Claims (4)

1. An umbrella jet fuel injector coupling, which is a precision coupling consisting of a needle valve and a needle valve body, with a tapered sealing section between the needle valve and the needle valve body, and a There is a through hole in the lower part of the section, and the head of the needle valve has an umbrella-shaped protrusion, and the protruding head passes through the through hole in the head of the needle valve body. The neck of the object adopts a rounded straight line tangential transition, smooth connection. 2. The umbrella injection nozzle assembly according to claim 1, characterized in that the lift of the umbrella injection injection nozzle assembly is 0.02mm-1mm. 3. The umbrella jet nozzle assembly according to claim 1, characterized in that: the tapered surface of the outlet of the needle valve body is provided with a round transition. 4. The umbrella jet nozzle assembly according to claim 1 or 3, characterized in that rounded or chamfered corners are provided on the edge of the head of the needle valve body.

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